This invention relates to voltage control devices and more specifically relates to a novel voltage control device which can be employed as a dimmer switch or fan speed control and which can be mounted in a conventional wall box.
Lamp dimmer switches are well known and commonly employ an operating shaft which can be pushed inwardly to electrically operate an air gap switch and can be rotated to cause the dimming of an output lamp which is operated by the switch. Such devices are commonly mounted within a conventional residential wall box and employ a power semiconductor circuit which regulates by phase control caused by adjustment of a resistor by rotation of the dimmer switch shaft.
Switches of the above type are commonly manufactured by separately mounting the various switch components directly on the conductive mounting plate or yoke of the switch with the component leads and terminals holding the parts in place and serving as points of electrical connection. Electrical insulating tape or tubing is commonly used to provide electrical isolation where necessary.
Dimmer switches of the above type have been simplified in construction and assembly through the use of a molded support which receives a control potentiometer and various electronic parts and a subassembled switch mechanism. This allows simpler assembly and reduces cost because the switch has become an integral part of the molded support structure.
It is also known to employ metal eyelets or rivets to fasten the main power semiconductor device to the yoke. Arrangements of this type also allow for fewer parts and simpler assembly of the dimmer switch. In such arrangements, however, the silicon chip in the semiconductor device must be electrically insulated from its heat sink tab since the metal eyelet used as the mounting member would otherwise short the device to the mounting plate. Such semiconductor devices are relatively expensive, and have reduced thermal heat transfer characteristics, which leads to reduced service life.